THE SPECIES. 25 



The trunk of the tree may reach a diameter of 5 or 6 feet and a 

 height of 150 feet. Its bark is yellowish in color, divided by deep 

 grooves into oblong areas of fairly uniform size. 



The wood of this tree is of large importance commercially, and 

 lumber from it is the principal product of many mills throughout 

 the timbered portion of the State of Montana. It is strong and 

 durable, and is much used in buildings and in various forms of 

 heavier construction. 



The rock pine (Pinus scopulorum) closely resembles the western 

 yellow pine, and there is considerable doubt as to whether it should 

 stand as a separate species. Some authors regard it as merely a 

 variety of Pinus ponderosa, while others consider it merely the 

 mountain form of this species. It is found from the Yellowstone 

 Park southward and mainly on the eastern side of the Divide. 



This tree may reach a height of 150 feet and a diameter of 5 or 6 

 feet. The bark is deeply furrowed. The leaves -occur in clusters 

 of 2 or 3, usually 3, are 4 to 6 inches long, and are bunched near the 

 ends of the branches. The cones may reach as much as 5 inches in 

 length, with scales thickened at the ends and armed with a sharp 

 recurved prickle. 



The lodgepole pine. Next among the pines from the standpoint 

 of distribution is the lodgepole (Plnus contorta). It occurs from 

 Alaska and the British possessions southward into Colorado and 

 California. It is found in all parts of the State of Montana west 

 of the Divide; in the central and eastern part more sparingly, 

 scattered in diminishing numbers along the river banks and the 

 higher elevations of land in the plains region. Its demands upon 

 soil moisture are somewhat greater than those of the yellow pine; 

 hence it flourishes upon northern slopes, on high ridges where win- 

 ter's snows lie deep, and far to the northward it forms dense 

 thickets around the mountain lakes. One of the characteristics of 

 the lodgepole forest is its density. It grows while young in almost 

 impenetrable thickets, but thins gradually with age to a stand of 

 clean and slender poles, and attains sometimes a foot or two in 

 diameter and a height of 50 to 100 feet. 



The leaves of the lodgepole pine are 2 to 3 inches long and are borne 

 in pairs. The cones are usually less than 2 inches in length, rather 

 sharply tapering and one-sided, the scales prickly. The cones hang 

 with persistency to the branches and open very slowly. Branches 

 may be found with the cones of 10 or more years still in position and 

 unopened. The reason appears to be that these cones do not always 

 dry sufficiently on the branch. Sometimes a fire singes the tops of 

 the trees. The heat, or the drying which follows the killing of the 

 tree, opens the cones and allows the seeds, which are small and light, 

 to be carried far and wide by the wind. The seeds of the lodgepole 



